Yet another GMC build

[Dieselwrencher]

Definitely looks awesome! I love how your truck has turned out!

[tantrumpipeline]

wow!! looks great!!

[OKGMC4]

Left last wednesday for Pigeon Forge TN. Spent three days at the Grand Run, and just got back last night. Awesome trip! 2 hours into the 14 hour drive my engine light came on telling me my knock sensor is malfunctioning. I also found out I still sit too low in the front, my passenger wiper gets stuck at 75mph, my rack and pinion is a little sloppy, my front driver caliper is missing a rattle clip, and I have an idler pulley that squeaks when cold. All that aside we drove it from Tulsa to Pigeon Forge and back at 75 mph getting 19 mpg even with the engine light on. I posted a few pics here...

http://67-72chevytrucks.com/vboard/s...d.php?t=543403

I have to thank my dad. He funded pretty much everything on the trip and even put up with me and my ocd without complaint. I think this kind of stuff is what these rods are all about. We went two years in a row in my moms 09 Challenger but this was better. Couldn't believe how much response the truck got.

I even found my long lost brother...

[Kim57]

Very cool.
Just sounds like a few minor things to work out and your good to go.
Kim

[Chevette]

"Couldn't believe how much response the truck got". And deservedly so. Your truck looks great. Thanks for the pics.

[_Ogre]

brother from a different mother ???
looking good!

[57bigwindow]

Your truck looks awesome I reference your thread often what a great build!

[Highsider]

Cool story and photos from the TN trip.

[OKGMC4]

So I drove over to the steel recyclers today and drove onto the scales. After subtracting my weight from the truck it weighs about 3500 lbs. Does this sound right?

I knew a V8, the stereo equipment, and A/C would add weight, but I also thought the C4 suspension cut a TON of weight off compared to the solid axle rear and I beam front. For some reason I thought it would be a little lighter, but that's still a lot lighter than most modern trucks.

[OrrieG]

Mine weighs 4500 with the extra cast iron transfer case and front axle so your weight does not seem that bad.

[_Ogre]

i went across the scales in my 09 sierra at the dump last week
i was shocked at 6300 lbs
no wonder my 58 gets better mileage than my 09

[1955GMC]

"I've been roughing in the cowl once I got the louvers removed and smoothed. Got to tell you it sucks. It's still not where I want it after 4 hours of trying to finish it with bondo. It's curved on two different planes and hard to sand with any conventional sander. You get one area right and you've taken too much out somewhere else."

Great truck build. There is a lot that can be taken away from your accomplishment. Thinking about what will work to improve your truck without going to catalogs and just buying the parts needed is inspirational. The tips on the wiper motor and electric fan are two good examples.
I have a question on how you filled in the cowl vent area. Did you just hammer the vents smooth and then weld or did you approach it by removing the louvers and adding material. It looks cool and I’d like to try that on my 55 GMC.

[OKGMC4]

In retrospect I think I did it the hard way. I hammered the louvers and welded them. Would have been less welding and grinding to just cut patches. If a guy had a planisher tool it would probably be even better to cut one large piece of steel and form it to fit that curve, then weld it into the middle of the cowl cover. I think Kabwe did this part way better than me in his build. His experience shows in his superior metal work. (But if the company who stamps these things new would just offer them "unlouvered" I know people would buy them.)

Thanks for the praise. Sometime it's a fine line between being creative and being cheap!

[1955GMC]

I saw Kabwe's cowl photo on January 11, 2011 but there is only the one (or did I miss another few?). It is hard to see how he did his in that photo angle. I agree about someone making these in the aftermarket. I looked thru on the online companies and I did not locate a vendor. This is a job I'm going to jump on AFTER I get the old girl up and running. I'm looking at this as a project that will never be 100% complete and the small stuff I'll jump on when I feel like it. Like you, I'm not a fan of body work and paint and if I work on it when I feel like it it will turn out better.
Thanks for the help.

[OKGMC4]

I think he had more pics on the old thread before he had to repost everything. Kim57 did the same thing here...

http://67-72chevytrucks.com/vboard/s...283107&page=11

...and there's lots of good pics.

[shadow1967]

I'm aliitle late. How great was that drive even with rattle and the noisy idler. And thanks. you give the rest of us HOPE that our project may end as happily. Thanks for the fan info, I copy and pasted it for reference later.

[OKGMC4]

Well, they say you're never done...


I've had a problem with the vette spring not handling the weight of a truck. It sat low and every time I hit a big bump it would bottom out on the front cross brace. Not fun. Then I got a stiffer Z51 spring to replace my base version and it was 1 inch higher but reallyy the same problem over again. Just too overloaded. About a month ago I bought a set of QA1 non adjustable shocks and a pair of 12" 400lb springs. Turns out that 400lb is still too weak (it sits 1 inch lower than planned with 1/2 inch more preload than recommended) but I gained another 2 inches of ride height and no more bottoming out. Now the BIG problem...

I put in the coilovers and got it aligned and it started pulling a little to the right. Then I got it realigned and it started pulling to the right again. I thought the mounts I made were moving but 3/16 steel doesn't give much. Third time around the alignment guy catches it...the mounting ears from the vette K member are turning in, which means the member is buckling. These were designed for the single leaf to push up from the inside. When I took out the leaf and put all the weight on the shock mounts instead it's warping the K member. Guess that's why Progressive Auto doesn't recommend the sheet metal K members in a C4 swap. Now I need a plan...

I need to bend the mounting ears back and gusset them. Pulling the motor and using a portapower might work but it's a pain. My dad says to make a plate that bolts onto the a arm mounts and weld an 8ft cheater to it and push down on it to bend it, but not sure it would supply the needed force. Then...once that is done I'm considering putting the weaker vette spring back in and dialing the coilovers down to minimum preload and running all three springs to get the right height AND stop the frame flex. Any thoughts or ideas?

[1955GMC]

I have never faced the problem before, but I'm from the more is better generation. If one spring is good three should be great.
Good Luck with that.
One thing I have to say is I'm glad you shared this bump in the "truck modification" road. Now I'm ready for a steering problem if I ever get finished. That truck of yours is beautifule eye candy.

[yossarian19]

I might not be seeing this correctly, but it looks like your coil over mounts are separate from the K member and are welded to the frame.
If so, I'd recommend strengthening both the coilover and uca mounts by connecting the two with a removable plate. Maybe a rectangle 3"x4" with ears that bend down & get secured by each upper control arm bolt & on both sides of the coilover bolt.
I think if you can tie that UCA mount in to something else & give it some structure you can keep the sheet metal K member with just your coilovers.

[hp1957]

OKGMC4, Mounts we made for both the 56 and 49 do NOT attach to the stock vette K-frame they go all the way through the 56 frame rails and on the caddy they attach to a heavy piece of box tubing that was added where the old cross member went. These were still both braced back to the vette k-member where the a-arms bolt. ITS BETTER TO OVER-BUILD being an ex-frame man I have seen lots of frames spread and flex and knew this would happen if we did not build having that considered in advance. ALLWAYS GO OVERKILL

From my bro Albert

Harvey

1957 Chevy Stepside
1958 GMC Fleetside C4 build thread: http://67-72chevytrucks.com/vboard/s...65#post5510465

[hp1957]

OKGMC4, If you look close you will notice the heavy gussets added to each side of the shock mounts. those were added to both the 56 and 49. the 49 has a "bolt on" brace from the mount back to the k-member because Mario wanted the k-member to be replaceable. The 56 using a much longer shock, we even added a solid piece of "bar stock" and welded it inside the upright shock mount for extra strength. The way we tied Marios k-members to the RE-ENFORCED frames help strengthen the k-member. I think it needs to all be built where the frame rails help the k-member and the k-member helps the frame before you even start to build shock mounts

From my bros Albert & Mario

Harvey
1957 Chevy Stepside
1958 GMC Fleetside C4 build thread: http://67-72chevytrucks.com/vboard/s...65#post5510465

[hp1957]

OKGMC4, check your pm.

Harvey
1957 Chevy Stepside
1958 GMC Fleetside C4

[OKGMC4]

Thanks for the pics, Harvey. Sorry about being out of it for awhile. I've been doing a honey-do task to the tune of 23 cases of ceramic tile in the kitchen, pantry, laundry room, walkway, and entryway for the wifey. Those sorts of things put the truck back of the list.

I took the advice to brace the mount back to the k member to heart. This weekend I used an angle finder with some steel and a c clamp to move the k member back into a 90 degree position. Glad it was this easy, as pulling the engine did NOT sound good. Once I got pulled into place I actually moved the k member over about 1/4 inch both sides. At this point I welded in sections of 2x2 1/8 wall square tube. They are welded to the k member, the frame, and the mounts. Should help keep it better. I also re installed my mega weak vette mono spring with no shims, and dialed my coil overs to the lowest recommended setting, 1/2" compression. This served two purposes...1. the frame never seemed to have a problem until the coil overs, maybe the vette spring kept tension in the right places to stop the twist?, 2.The vette spring was too weak by itself and 400 lb 12" springs were slightly too weak (you are right that 500 might have been more appropriate) but together they work well. The truck definitely sits higher now but seems to ride well and corners great. The mono spring acts to help out the tiny front sway bar as well. I don't think this thing could bottom out now if I wanted it to. If you have any suggestions or think this won't work let me know.

[Wheelie]

I feel your pain on the spring bind, I learned the hard way on a few customer cars. If you went with a stiffer rate like I would guess 550 or even more with an adjustable shock you would get rid of that spring bind. If I remember correctly the spring should only be preloaded 25% of its total unbound length If you didnt already know. HTH!

[OKGMC4]

I realized I hadn't taken any pics of the truck since the front suspension change so I tried to take some good ones yesterday. I waited until days end to get a better diffuse light and tried different angles on the top level of a parking garage. Didn't realize how hard it is to get one where there's no wash out, I deleted several where it looked white on top and orange on the bottom. I't also hard to avoid reflections of other things in the paint and shadows in odd places. Not really a photographer but a few turned out nice.

As far as the front goes it's a ton higher now but it drives great and never ever bottoms out so I guess I'll leave it alone. It could possibly benefit from going from a 1" front bar to a 1.25 bar as I think my nose heavy weight is taxing the lean in the turns. It's not really bad, mind you, but I'm trying to get sports car handling and with C4 suspension it should be attainable. Though I am frustrated. I live close to a road course, Hallet racing, and would be willing to pay the fees and take the driving class to do the course but they have a strict NO TRUCKS rule that I think is asinine. I could run my base model, underbraked, 170hp 92 firebird there but not my C4 suspended LS powered 1956 gmc !!!